                1. Field of the Invention        
The present invention relates to a printer with an ink cartridge attached thereto that carries out printing by the unit of dots, as well as to an ink cartridge detachably attached to a main body of the printer. More specifically the invention pertains to a technique of storing information into the ink cartridge.                                    2. Description of the Related Art                        
The printing apparatus like the ink jet printer and the ink jet plotter mainly includes an ink cartridge, in which one or plural inks are kept, and a printer main body with a print head to carry out actual printing operations on a printing medium. The print head transfers ink fed from the ink cartridge onto the printing medium, such as printing paper, so as to implement printing on the printing medium. The ink cartridge is designed to be detachably attached to the printer main body. A new ink cartridge has a predetermined quantity of ink kept therein. When the ink kept in an ink cartridge runs out, the ink cartridge is replaced with a new one. Such a printing apparatus is arranged to cause the printer main body to calculate the remaining quantity of ink in the ink cartridge based on the amount of ink transferred from the print head and to inform the user of a state of running out of the ink, in order to prevent the printing procedure from being interrupted by the out-of-ink.
The data on the remaining quantities of inks are generally stored only in the printer main body or in a printer driver that controls the printer. In the event that a first ink cartridge is replaced with a second ink cartridge in the course of the printing operation, the information relating to the first ink cartridge, such as the data on the remaining quantities of inks, are thus lost or made wrong.
One proposed technique to solve this problem utilizes a non-volatile memory provided in the ink cartridge and causes the required data, for example, the data on the remaining quantities of inks, to be written from the printer main body into the non-volatile memory (for example, JAPANESE PATENT LAID-OPEN GAZETTE No. 62-184856). In the case of replacement of the ink cartridge during the printing operation, this technique ensures the storage of the data on the remaining quantities of inks.
The ink cartridge attached to the printer is expendable. A non-volatile memory generally used in the printer, for example, a large-sized, expensive non-volatile memory having a relatively large storage capacity of several kilobytes and more than ten terminals, is not applicable for the ink cartridge. Using such a non-volatile memory makes the ink cartridge undesirably bulky and increases the manufacturing cost of the expendable ink cartridge, which is abandoned after the ink kept in the ink cartridge runs out.
One proposed technique accordingly applies a small-sized special non-volatile memory having a relatively small storage capacity for the ink cartridge. The non-volatile memory with only several terminals adopts a specific format of addressing, which is different from the format of addressing adopted in the general non-volatile memories. This accordingly arises another problem of difficulty in handling.
In the case where the different format of addressing is adopted, the computer that controls the writing operation of data may carry out conversion of the format of addressing. In the case of an ink cartridge having an ink reservoir, in which a plurality of different inks are kept, and holding required pieces of information, for example, pieces of information on the amounts of ink consumption, independently with regard to the respective inks, however, there are relatively long data lengths to be written and the address conversion requires an undesirably long time. Such a disadvantage is not negligible since it may cause all the data to be not rewritten when no sufficient time period is provided for the address conversion, for example, at the time of forcible cut-off of power supply.
The problems discussed above arise in any printing apparatus that does not directly measure the remaining quantity of ink or the amount of ink consumption in an ink cartridge but causes the printer to compute such data, and in an ink cartridge attached thereto. Such printing apparatus includes an ink jet-type printing apparatus that uses ink obtained by mixing or dissolving a pigment or a dye with or in a solvent and transfers ink droplets in the liquid state to implement printing, a printing apparatus that uses an ink cartridge with an ink toner accommodated therein, and a thermal transfer-type printing apparatus.